Muse Spark 1.3 Is Now FREE on OpenCode! Zen & Go Guide 2026 (Contributor Tier Explained)

"Meta's Muse Spark 1.3 is supposedly amazing, but how much does it cost?"

Released September 2, 2026, Muse Spark 1.3 is Meta's most powerful coding model — DeepSWE 75.4 (above Opus 5), MRCR long-context 98.5. Meta's own API is already cheap at $0.10/1M input (Contributor), but did you know it is completely free through OpenCode?

Bottom line: OpenCode Zen (or the $10/month OpenCode Go plan) gives you access to Muse Spark 1.3 Contributor at no extra cost. The catch: the "Contributor" version is free only because you allow your prompts and outputs to be used for training future Meta models.

What you'll learn

Why Muse Spark 1.3 is free on OpenCode Zen/Go
4-step setup guide
What "used for training" really means (and cautions)
Contributor vs Standard tier differences
Why Muse Spark 1.3 performance is genuinely frontier-level
OpenCode Go affiliate info (ja article)

Why Muse Spark 1.3 is genuinely impressive

Muse Spark 1.3 is the latest coding/agent-focused model from Meta Superintelligence Labs (MSL) — the 4th major update in 5 months. It matches or beats frontier models (Opus 5, GPT-5.6 Sol) on key benchmarks:

DeepSWE v1.1: 75.4 (above Opus 5's 74.0)
MRCR 256K-512K: 98.5 (well above GPT-5.6 Sol's 91.5)
MRCR 512K-1M: 98.1 (best-in-class ultra-long context)
Terminal-Bench 2.1: 88.8 (tied with GPT-5.6 Sol)
~20% fewer tool calls, ~25% fewer tokens vs 1.2

Importantly, the model is positioned as "training-eligible." Meta's strategy: frontier-level performance in exchange for your data helping train future models — which is why the price can be near zero.

How free access works on OpenCode Zen/Go

4 steps to use Muse Spark 1.3 Contributor for free on OpenCode

Contributor tier (Meta's discounted tier)

Meta Model API has two pricing tiers:

Tier	Input (1M)	Output (1M)	Training use
Contributor (discounted)	$0.10	$0.20	Consent required (used to train Meta models)
Standard	$1.25	$4.25	Not used for training

Contributor tier means: "heavily discounted token pricing in exchange for permission to use your prompts and completions to train future Meta models" (per dev.meta.ai).

OpenCode Zen: completely free ($0)

The OpenCode Zen model catalog includes "Muse Spark 1.3 Contributor Free" (muse-spark-1.3-contributor-free) priced at $0. Zen's privacy policy states the same: heavily discounted pricing in exchange for permission to train Meta models on your data. OpenCode has a special arrangement with Meta and absorbs the cost.

OpenCode Go ($10/month): also included

OpenCode Go is a $10/month flat subscription giving unlimited access to popular open models like DeepSeek V4 Flash, Qwen3.8 Flash, and GLM-5.3-Flash. Its model list includes "Muse Spark 1.3 Contributor (limited regions)" with a huge 45,300 requests per 5 hours (far above DeepSeek V4 Flash's 11,400).

So $10/month on OpenCode Go gives you both DeepSeek V4 Flash AND Muse Spark 1.3 — an incredible combination.

4-step setup

Step 1: Create an OpenCode Zen/Go account

OpenCode Zen: sign up at opencode.ai (pay-as-you-go; free models cost $0)
OpenCode Go: $10/month subscription (recommended — flat rate, all models)

Step 2: Get an API key

Issue an API key from the Zen dashboard. Go subscribers reuse the same key. The endpoint is OpenAI-compatible, so you can use it from any agent, not just OpenCode.

Step 3: /connect + /models

# In the OpenCode TUI
/connect    # select OpenCode Zen, paste your API key
/models     # view the model list

Select "Muse Spark 1.3 Contributor Free" (muse-spark-1.3-contributor-free).

Step 4: Start coding

Use it like normal OpenCode. It shines on long-repo refactoring, agentic work, and multi-file edits.

Cautions: what "used for training" actually means

What is used? Your prompts and the model's completions
Used for what? Training future Meta models
Never submit: confidential info, personal data, trade secrets, production customer data
To opt out: use the Standard tier ($1.25/$4.25) instead
Enterprise policy? If your company forbids training on your data, do not use Contributor Free. For personal projects, learning, and prototypes it is fine

In short: nothing is truly free. The trade-off is that your code and questions help improve Meta's models — understand it and choose the right tier.

Summary

OpenCode Zen/Go lets you use frontier-level Muse Spark 1.3 for free (or $10/month).

✅ Muse Spark 1.3 Contributor Free = $0 on Zen
✅ OpenCode Go = $10/month includes Muse Spark 1.3 Contributor + all top open models
✅ Performance: DeepSWE 75.4 (above Opus 5), MRCR 98.5
✅ Caveat: Contributor tier trains Meta models on your prompts/outputs
✅ If training use is forbidden: choose Standard ($1.25/$4.25)

Frontier performance, free in exchange for training data — for individual developers this is a huge opportunity. Try it today.